vertical-motion in CVS emacs

[Peter Heslin]

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Please write in English if possible, because the Emacs maintainers
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Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

The function vertical-motion doesn't seem to work as advertised in
current CVS emacs.  When encountering a line that wraps, because it is
longer than can fit in the width of the frame, vertical-motion gets
stuck.

Take a long line like this:

blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah 
blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah 
blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah 
blah blah 

and put the cursor above it.  Then repeatedly do:
M-: (vertical-motion 1) RET

The cursor will get stuck at the start of the second screen line in
the middle of the long line and refuse to move down any further.

(vertical-motion -1) also misbehaves, but in a different way, jumping
over and failing to stop at each screen line.

I ran into this problem when using screen-lines.el, an external
package which uses vertical-motion to do its work.

This is with a fresh checkout of emacs from gnu arch
(address@hidden/emacs--cvs-trunk--0, because the CVS server
at savannah.gnu.org was down), and I confirmed that this also happened
when running emacs -q --no-site-file.



In GNU Emacs 21.3.50.2 (i686-pc-linux-gnu, GTK+ Version 2.2.1)
 of 2004-07-02 on vectra
configured using `configure '--with-x-toolkit=gtk''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_GB
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  eldoc-mode: t
  outline-minor-mode: t
  msb-mode: t
  iswitchb-mode: t
  cua-mode: t
  mouse-sel-mode: t
  show-paren-mode: t
  recentf-mode: t
  encoded-kbd-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  temp-buffer-resize-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t
  flyspell-mode: t

Recent input:
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <menu-bar> 
<help-menu> <report-emacs-bug>

Recent messages:
Loading pcmpl-darcs (source)...done
Loading /home/pj/elisp/emacs-pjh.el (source)...done
Loading /home/pj/.session...done
Error: No fold-making function associated with this mode
Ispell process killed
(Next local Ispell command will use american dictionary) [2 times]
Starting new Ispell process...
Loading eldoc...done
Loading jit-lock...done
Loading emacsbug...done